1. Field of the Invention
The present invention relates generally to containers that include an internal module that adds heat to or removes heat from the material, such as a food, beverage, medicine, or the like, in the surrounding container.
2. Description of the Related Art
Containers may have integral modules for warming materials in the container, such as Japanese sake, coffee, or soup. Examples of such self-heating containers are disclosed in U.S. Pat. Nos. 5,461,867 and 5,626,022, issued to Scudder et al. Such containers typically include an outer can or body, in which the food or beverage is sealed, and an inner can or thermic module that contains two chemical reactants that are stable when separated from one another but, when they mix in response to actuation of the thermic module by a user, produce an exothermic reaction or, alternatively, an endothermic reaction and thereby heat or cool the contents of the container.
The heating or cooling module (thermic module) is typically attached at one end of the cylindrical container body, and the elongated cylindrical reaction chamber portion of the module extends into the container body. This elongated portion functions as both a chamber in which to contain the reaction and a heat-exchanger for transferring heat between it and the surrounding contents of the container body. The thermic module has two chambers, each of which contains one of the chemical reactants, separated by a breakable barrier such as metal foil or a thin plastic film. Typically, one of the reactants is a liquid, and the other is in a solid powdered or granular form. Calcium oxide and water are examples of two reactants known to produce an exothermic reaction to heat the contents in such containers. Other combinations of reactants are known to produce endothermic reactions to cool the container contents. A cap containing the liquid reactant is disposed in the end of the thermic module attached to the container body. At one end of the cap is an actuator button that a user may press to initiate the heating or cooling. The barrier seals the other end of the cap. The cap has a pushrod or similar prong-like member that extends from the actuator button nearly to the barrier. Depressing the actuator button forces the prong into the barrier, puncturing it and thereby allowing the liquid reactant to flow into the solid reactant in the reaction chamber. The heat produced by the resulting exothermic reaction or used by the resulting endothermic reaction is transferred between the reaction chamber of the thermic module and the contents of the container body by conduction. Exothermic reactions also typically generate a gas and/or steam, which is allowed to escape through vents in the end of the container. The user inverts the container and, when the contents have reached the desired temperature, consumes the contents. The second end of the container body has a seal or closure, such as a conventional beverage can pull-tab, that may be opened and through which the user may consume the heated or cooled contents.
A portion of the thermic module, such as the elongated cylindrical reaction chamber, may be unitarily formed with the outer can, as illustrated, for example, in U.S. Pat. No. 3,970,068, issued to Sato, and U.S. Pat. No. 5,088,870, issued to Fukuhara et al. The unitary container body is formed by providing a metal cylinder that is open at one end and closed at the other, and punching or deep-drawing a cavity in the closed end. A cap containing the liquid reactant is attached to the open end of the cavity. In other such containers, however, the elongated cylindrical reaction chamber may be separately formed and then attached to the container body by another manufacturing step. It would be desirable to provide an economical and reliable method for manufacturing this latter type of container.
Another problem associated with self-heating and self-cooling containers is that a person may attempt to consume the contents before the contents have been fully heated or cooled. That the person may be displeased by the resulting temperature of the beverage or other contents is not the only effect. A perhaps more serious effect is that a self-heating container may overheat and present a burn hazard if, after the user empties it of its contents, it continues to generate heat, because the contents act as a heat sink. It would be desirable to provide a self-heating container that inhibits a user from consuming the contents before the heating reaction has completed.
As disclosed in the above-referenced U.S. patents, the actuator button may be protected by a foil safety seal. An unbroken seal assures a person that the container has not been actuated and is thus ready for use. Also, the reactivity of typical chemicals such as calcium oxide may decrease if they absorb atmospheric moisture, such as could occur if the container were in storage or in transit for prolonged periods in a moist environment prior to use, and the seal inhibits exposure of the reactants to atmospheric moisture. To use the container, the user peels the foil seal off the container and discards it. The removal of the foil seal presents a disposal problem because the user may not be within a convenient distance of a trash receptacle. It would further be desirable to minimize disposal problems associated with self-heating and self-cooling containers.
These problems and deficiencies are clearly felt in the art and are solved by the present invention in the manner described below.
The present invention relates to a container having a container body, a thermic module at one end of the body, and a closure at the other end of the body. The body may have any suitable generally tubular shape, such as cylindrical or can-shaped or bottle-shaped. The food, beverage, medicine or other material to be heated or cooled is contained in a material cavity in the container body. The thermic module contains a chemical reactant that is segregated from another reactant in the container. When a user actuates the thermic module, the reactants mix and produce a reaction that, depending upon the reactants, either produces heat, i.e., an exothermic reaction, and thereby heats the container contents, or uses heat, i.e., an endothermic reaction, and thereby cools the container contents.
In accordance with one aspect of the present invention, a plastic thermic module body is spin-welded to a plastic container body by rotating one relative to and in contact with the other. The frictionally generated heat fuses or welds the contacting plastic surfaces together. The container body may have multiple layers, including an oxygen and flavor scalping barrier layer that inhibits oxidation and spoilage of the contents. Spin-welding the container body to the module body in this manner seals the portion of the inner layer that is exposed at the annular end of the container body between two plastic layers and thereby prevents air or moisture from seeping past the outer plastic layer and into the inner layer.
In accordance with another aspect of the present invention, the container includes a movable cover mounted over the closure. A suitable heat-sensitive adhesive between the cover and the container inhibits movement of the cover until the temperature has reached a certain threshold. The adhesive bond softens when the adhesive reaches approximately that temperature. In an exemplary embodiment of the invention, the cover is rotatable. The cover has an opening, and when the threshold temperature is reached, the user can rotate the cover until the opening is aligned with the closure. The user may then open the closure and consume the contents of the container.
In accordance with still another aspect of the invention, the thermic module includes a seal, such as a foil disc, between an inner actuator button and an outer actuator button. The inner actuator button may be included in a module cap that holds the solid reactant. The outer actuator button has one or more apertures and also has one or more prongs directed toward the seal. When the user presses the outer actuator button, the prong punctures the seal. This actuator structure eliminates the disposal problem associated with a removable foil seal. In addition, if for some reason the module cap were to become overpressurized prior to use, the pressure would force the inner actuator button against the seal. The seal, in turn, presses against the prong and punctures it, thereby relieving the pressure through the apertures in the outer actuator button.
The thermic module may also include a filter disposed in interfering relation with the vents between the inner and outer actuator buttons to block egress of any particles of the solid reactant or the reaction product, and also absorbs water (gaseous and liquid) during the reaction. The filter may include a disc-shaped portion between the inner and outer actuator buttons and an annular portion between flanges coupled to the actuator buttons. The disc-shaped portion may be integrally formed with the annular portion prior to assembly of the container and separated from one another along an annular perforation line during a manufacturing step in which the filter portions are inserted into the thermic module.
The foregoing, together with other features and advantages of the present invention, will become more apparent when referring to the following specification, claims, and accompanying drawings.